Electrical connector with preplaced solder



n 5, 1967 H. P; SHERL-OCK 3,

ELECTRICAL CONNECTOR WITH PREPLACED SOLDER Filed Aug. 23, 1965 2Sheets-Sheet l 1&1.

lNVE NTOR. 06 406 57/56ZOCZ BY W June 6, 1967 H. P. SHERLOCK 3,324,230

ELECTRICAL CONNECTOR WITH PREPLACED SOLDER Filed Aug. 23, 1965 2Sheets-Sheet 2 W .24 BY United States Patent 3,324,230 ELECTRICALQONNECTOR WITH PREPLACED ULDER Hugh Paul Sherlock, Menlo Park, Calif,assignor to Raychem Corporation, Redwood City, Calif., a corporation ofCaiifornia Filed Aug. 23, 1%5, Ser. No. 481,534 22 Claims. (Cl. 174-84)This invention relates to an electrical connector and more particularlyrelates to an electrical terminal having a pre-installed wire connectorthereon.

In Wetmore application Ser. No. 211,747 filed July 23, 1962, now PatentNumber 3,243,211, several types of novel electrical connectors aredisclosed. The electrical connectors of the Wetmore application, thedisclosure of which is incorporated by reference herein, include adimensionally heat unstable member such as a sleeve in which is placed asolder insert. In a typical connector of this type, both ends of themember or sleeve are open to receive the electrical conductors that areto be connected. The connectoris then heated causing the member orsleeve to shrink and firmly grip the electrical conductors. The heatalso causes the solder to flow and form a soldered connection betweenthe two electrical conductors. The sleeve acts to contain the movementof the solder so that a good soldered joint is assured.

In general, such members or sleeves are made of a material having theproperty of plastic or elastic memory and are expanded under heat andpressure to a diameter greater than their normal diameter and cooledwhile kept under pres-sure. A sleeve treated in this manner will retainits expanded position until it is again heated to above its heatrecovery temperature at which time it will recover to its originalshape. Examples of materials useful in forming such dimension-ally heatunstable recoverable members may be found in Currie Patent 2,027,962 andCook et al. Patent 3,086,242, the disclosures of which are incorporatedherein by reference. Polymeric materials which have been cross-linked bychemical means or by radiation, for example, with high energy electronsor nuclear radiation, such as those disclosed in the Cook et al. patentare preferred for use in the present invention. Non-crystallinepolymeric materials exhibiting the property of plastic or elasticmemory, such as polyurethane, ionomers, etc., could also be used inpracticing the present invention.

In Hess application Ser. No. 446,246 filed Apr. 7, 1965, there are shownvarious types of electrical connectors made in accordance with theWetmore invention and apparatus for simultaneously making a plurality ofelectrical connections, for example, between a plurality of wires and aplurality of terminals. While the electrical connectors of the typedisclosed in the aforementioned Wetmore and Hess applications are quiteuseful, there are some occasions where it would be desirable to have aconnector pre-installed on a conductor such as a terminal pin so thatonly one conductor, rather than two, need be inserted into and held inplace in the sleeve before it is heat recovered. In many instances thiswould greatly simplify the making of an electrical connection and permitterminal pins or the like to be provided that could be spaced very closeto one another.

It is also desirable that the skill required of the operator making theconnections be made as low as possible. By providing a predeterminedamount of solder in the sleeve, the devices disclosed in the previouslymentioned applications greatly reduce the skill required to make a goodconnection. However, problems can still arise, and faulty connectionsresult, because of the need to properly locate the two conductors to besoldered and then pre- 3,324,230 Patented June 6, 1967 venting theirrelative movement during cooling of the solder. It would therefore be ofgreat benefit if the probability of mislocation could be reduced oreliminated. The pro-installation of a connector such as a heatrecoverable sleeve on one of the conductors would serve to cause such areduction as only one of the conductors would now need to be properlypositioned.

It is accordingly an object of the present invention to provide anelectrical conductor, such as a terminal pin, having a pre-installedwire connector mounted thereon.

It is another object of the present invention to provide such aconductor in which the pre-installed wire connector serves to properlylocate a wire With respect to the conductor for a soldering operation.

It is also an object of the present invention to provide such aconnector wherein the amount and characteristic of the solder bepredetermined and controlled at the time of the manufacture of theconductor.

These and other objects and advantages of the present invention willbecome more apparent upon reference to the accompanying description anddrawings in which:

FIGURE 1 is a top plan view of a plurality of terminal pins constructedin accordance with a first embodiment of the present invention;

FIGURE 2 is a cross-sectional view taken along lines 2--2 of FIGURE 1;

FIGURE 3 is an enlarged sectional view taken along line-s 33 of FIGURE1;

FIGURE 4 is a top plan view of one of the terminal pins of FIGURE 1after a heat recoverable sleeve has been installed thereon;

FIGURE 5 is a sectional view taken along lines 5-5 of FIGURE 4;

FIGURE 6 is an enlarged sectional view of the terminal pin of FIGURE 4after a soldered connection has been made and the heat recoverablesleeve recovered;

FIGURE 7 is a cross-sectional view taken along lines 77 of FIGURE 6;

FIGURE 8 is the cross-sectional view illustrating how the terminal pinsof FIGURE 1 are positioned in a terminal block;

FIGURE 9 is a cross-sectional view taken along lines 99 of FIGURE 8;

FIGURE 10 is a cross-sectional view of a second embodiment of a terminalpin having a pre-installed wire connection thereon;

FIGURE 11 is a cross-sectional view taken along lines 11-11 of FIGURE10;

FIGURE 12 is across-sectional view of the third embodiment of a terminalpin having a pre-installed wire connector installed thereon;

FIGURE 13 is a cross-sectional view taken along lines 1313 of FIGURE 12;

FIGURE 14 is a plan view of a mandrel used in pre-installing heatrecoverable sleeves on the terminal pins of the first embodiment of thepresent invention; and

FIGURE 15 is a cross-sectional view showing the mandrel of FIGURE 14 inuse.

Briefly, the present invention is directed to a terminal pin or similarelectrical conductor on which is firmly installed a heat recoverablesleeve which has one end open to receive another electrical conductor.The terminal pin is provided with a body of solder and flux which may becoated on the pin in any suitable manner or deposited in a recess formedin the pin. The amount, type and shape of the solder is predetermined atthe time of the manufacture of the pin. The sleeve is preferablypre-formed so that the conductor is automatically positioned on theterminal when it is inserted into the sleeve. When heat is applied, thesleeve shrinks and presses the conductor against and through the solderas the solder melts and holds it there as the solder cools.

In the preferred embodiment, the terminal pin is provided with a seriesof recesses into which the sleeve recovers so that a strong and reliableconnection is assured. The terminal pins can be produced in strips andthe solder and sleeves then installed while the pins are still in stripform. Individual pins can then be separated and used as needed. Ifdesired, the pins may be installed directly on the ends of cables orother conductors and then snapped into a suitable terminal block insteadof first snapping the pin into the block and then installing the cableor conductor.

Turning now to the drawings, FIGURE 1 shows a strip of terminal pinsconstructed in accordance with a first embodiment of the presentinvention. Each of the pins is connected to a carrier strip 12 and toeach other by scored joints 14. Each pin 10 is provided with an offset,spring-like terminal tang 16, the end of which extends above the surfaceof pin 10 and which serves to position and hold the terminal in aterminal block as will be seen in connection with FIGURES 8 and 9. Theterminal pins 10 are also provided with first and second pairs oflateral indentations or recesses 18 and 20 on the side surfaces and arecess 22 on the top surface. The recess 22 receives a body of solder24, the body of solder extending along an appreciable length of the pin10 so that a fairly large surface area is provided as can be seen inFIGURE 3. The body of solder 24, of course, includes a suitable flux,the amount of solder and flux being predetermined for optimum results.

In FIGURES 4 and 5, each of the terminal pins 10 has been provided witha dimensionally heat unstable tubular member or sleeve having aconfiguration optimally suited for receiving an electrical conductor.Although only a single pin is shown in FIGURES 4 and 5, it should beunderstood that in practice a sleeve is installed on each of the pins 10attached to thecarrier strip 12 shown in FIGURE 1. An electricalconductor 32 having a conductive portion 34 and an insulating portion 36is inserted into the sleeve 30. As can be seen from the various Figures,the ends of the pins are rounded to prevent any damage to the conductorwhen it is flexed.

The configuration of the sleeves shown in FIGURES 4 and 5 may beobtained in the following manner. A tubular sleeve is positioned overeach terminal pin 10, and a mandrel, such as that indicated generally at40 in FIGURE 14 is then positioned over the terminal pin strip. For thispurpose, the mandrel 40 is comb-like in structure and is provided with aplurality of teeth 42 each having a tip 44 of reduced size. The teeth 42are joined by rounded regions 46. As can be seen in FIGURE 15, each ofthe teeth 42 of the mandrel 40 is inserted into a sleeve 30 surroundingeach of the terminal pins 10 in such a manner that the end of thereduced tip 44 of the tooth 42 extends to the end of the solder body 24.If, as illustrated, the amount of solder positioned in the recess 22 issuch that it protrudes above the recess, the reduced tip 44 of the tooth42 is undercut so that the tip 44 will slide smoothly over the body ofsolder 24. Preferably, the upper surface 48 of the tooth 42 is inclinedand the incline continues beyond the end of the sleeve 30 so that themandrel can relatively easily be withdrawn from the sleeve 30 and theterminal pin 10 after the sleeve has been shrunk. Of course, the teeth42 are spaced apart by a distance equal to the spacing between pins 10and the width of the main portion of the teeth are made substantiallyequal to the width of the terminal pins.

After the mandrel has been placed in position, heat is very brieflyapplied to the sleeves 30 causing them to shrink down around the pins 10and the teeth of the mandrel. Since the crystalline melting temperatureof the material from which the sleeves are made is below that of themelting temperature of the solder, a brief application of heat willcause the sleeves to shrink without causing the solder or flux to meltor flow. This efiect can also be enhanced by constructing the mandrel ofa material having relatively poor heat conduction characteristics sothat heat is not transferred to the solder before the sleeve has 'beenshrunk. The mandrel is now removed from the formed sleeves. The shape ofthe sleeves after this first heating operation can be seen in FIG- URES4 and 5.

The sleeve has shrunk into the first pair of indentations 18 formed inthe terminal pin because the reduced tip 44 of the tooth 42 of themandrel did not extend laterally outward far enough to prevent this.However, the main portion of the tooth did extend out to the edge of thepin 10 in the region of the indentations 2t) and hence the sleeve hasnot shrunk into these indentations. The tip 44 has also prevented thesleeve 30 from engaging the solder body 24 and hence ha left a spacesufficient to receive the conductive portion or wire 34 of theelectrical conductor 32. The inclined portion 48 of the tooth 42 hasleft the sleeve 30 at a similar incline so that easy access is providedfor the conductor 32. Since the sleeve has shrunk down into engagementwith all the other surfaces of the terminal pin 10, there can be nomistake made in placing the wire into the sleeve. The terminals are nowcomplete and ready for use.

FIGURES 6 and 7 illustrate the position of the various elements of theassembly after a wire has been inserted and the final heating operationcompleted. As can be seen, when the assembly is heated to above thecrystalline melting temperature of the material of the sleeve 30 and themelting point of the solder 24, the sleeve 38 shrinks around theinsulation 36 of the conductor 32 and causes conductive portion 34 to bepressed against the solder. As the heating continues, the flux flows toprepare the surfaces and then the solder melts to form the joint. Thesleeve 30 continues to shrink, pressing the wire into the molten solderwhile at the same time controlling the flow of the solder. Upon cooling,the solder h-ardens and the sleeve cools to provide an insulatedmechanically supported solder connection.

Since it is good practice in soldering to bring the temperature of themetals to be soldered up to the temperature necessary to melt the solderbefore the solder is actually melted, heat is preferably first appliedto the sleeve on the side of the wires so that the Wire must be heatedfirst because it is closest to the heat source. This consequentlyinsures that the wire is up to proper soldering temperature. Theshrinking action of the sleeve as- I s-ures close proximity of themetals to be joined and lack of movement during cooling, tworequirements which must be met for good solder joints. As the sleeve 30shrinks, it follows the contour of the pin and thus enters theindentations 20 creating a positive mechanical look between the sleeveand the terminal pin 10.

FIGURE 8 illustrates a convenient manner in which the individualterminal pins 10 maybe used after they are removed from the connectingstrip 12. A terminal block 50 of a suitable insulating material isprovided with a passageway 52 having an offset shoulder 54 for eachterminal pin 10. The terminal pin 10 is slid into the passageway 52 fromthe right hand side until the tang 16 clears the shoulder 54 at whichtime it flexes upwardly to lock the pin 10 against outward movement. Theterminal pin can be simply removed by inserting a pin 56 into the otherend of the passageway 52. The pin 56 will serve to depress the tang 16so that the pin 10 can be pulled clear.

Turning now to FIGURES 10 and 11, there is shown a second embodiment ofa terminal pin according to the present invention. In this embodiment,the terminal pin 60 is shown as circular in cross-section although itcould, of course, have any desired cross-section. A body of solder'62 ispositioned around the entire periphery of the terminal pin 60 andextends along an appreciable length of the pin 60. A heat recoverablesleeve 64 is positioned over the terminal 60 and solder 62 and theportion of the sleeve between the body of solder 62 and the inner end ofthe pin 60 is shrunk down into engagement with the terminal pin 60. Thisshrinking can be accomplished by local heating or by the use of asuitable mandrel as will be obvious to those skilled in the art.

A conductor 66 may now be inserted into the annular space between thebody of solder 62 and the sleeve 64 such that the conductive portion 68of the conductor 66 overlies the solder body 62. The remainder of thesleeve 64 now can be heat recovered so that it will tightly engage theinsulation of the conductor 66 and control the flow of the solder 62which will be caused to melt by the same application of heat. Ifdesired, of course, the solder could be positioned on only a limitedportion of the circumference of the pin 62 and the sleeve 64 shrunk downto engage the pin except in the area of the solder so that a morerestricted opening for receiving the conductor 66 is provided.

FIGURES 12 and 13 show a third embodiment of the present invention. Inthis embodiment, the terminal pin 70 is either V-shaped along its entirelength or is provided with 'a trough at its outer end. A body of solder72 is provided in this trough and a heat recoverable sleeve 74positioned around the terminal pin and shrunk into engagement with theterminal pin in a region lying between the body of solder 72 and theinner end of the pin 70. The sleeve 74 is preferably also shrunk intoengagement with the pin 70 on the side of the pin opposite to the bodyof solder 72. A conductor 76 having a conductive portion 78 may now beinserted into the sleeve 74 and the sleeve shrunk in the same manner aswas done in FIGURES and 11 to make a good solder contact which ismechanically strengthened by the engagement of the sleeve 74 with theinsulation of the conductor 76.

From the foregoing description, it can be seen that the presentinvention provides an electrical connector which is simple and sturdyand which allows close spacing between terminal pins. The solder, fluxand insulating sleeve are already packaged on the. terminal pin,eliminating the need of any'bulky applicators. Heat may be applied to'many pins simultaneously from distant hot air or infrared sources, thuseliminatingv the need for room around the pins for installation tools.The sleeves may be constructed of a transparent material so that thesoundness of thes older connection can be visually inspected.

The invention may be embodied in other specific forms not departing fromthe spirit or central characteristics thereof. The present embodimentsare therefore to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than by the foregoing descrip tion', and all changes whichcome within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

I claim:

1. An electrical connector comprising an elongated electricallyconductive member; a body of solder positioned on said conductive memberadjacent one end thereof and extending along an appreciable length ofsaid conductive member; and a dimensionally heat unstable tubular memberpositioned over said one end of said conductive member and the body ofsolder positioned thereon, the longitudinal axis of said tubular memberbeing substantially parallel to the longitudinal axis of said conductivemember, a portion of said tubular member being in intimate engagementwith said conductive member in a region of said conductive memberbetween said bod of solder and the other end thereof.

2. An electrical conductor comprising an elongated electricallyconductive member; a body of solder positioned on said conductive memberadjacent one end thereof and extending along an appreciable length ofsaid conductive member; and a dimensionally heat unstable tubular memberpositioned over said one end of said con-ductive member and the body ofsolder positioned thereon, the longitudinal axis of said tubular memberbeing substantially parallel to the longitudinal axis of said conductivemember, a portion of said tubular member being in intimate engagementwith said conductive member in a region of said conductive memberbetween said body of solder and the other end of said conductive member,the remainder of said tubular member having at least a portion thereofspaced from said conductive member for receiving an electrical conductorbetween said tubular member and said conductive member.

3. An electrical conductor comprising an elongated electricallyconductive member; a body of solder positioned on said conductive memberadjacent one end thereof and extending along an appreciable length ofsaid conductive member; and a dimensionally heat unstable tubular memberpositioned over said one end of said conductive member and the body ofsolder positioned thereon, the longitudinal axis of said tubular memberbeing substantially parallel to the longitudinal axis of said conductivemember, a portion of said tubular member being in intimate engagementwith a region of said conductive member of substantial longitudinaldimension located between said body of solder and the other end of saidconductive member, the remainder of said tubular member having at leasta portion thereof spaced from said conductive member for receiving anelectrical conductor between said tubular member and said body of soldersuch that the longitudinal axis of said conductor is substantiallyparallel to that of said conductive member.

4. The connector of claim 1 wherein the melting temperature of said bodyof solder is above the heat recovery temperature of said tubular member.

5. The connector of claim 1 wherein said tubular member comprises across-linked polymer.

6. The connector of claim 5 wherein said tubular member comprises anirradiated polymer.

7. The connectors-of claim 1 wherein said conductive member is provided.with a recess in one surface thereof, said body of solder beingpositioned in said recess.

8. The connector of claim 1 wherein said body of solder is disposedaround the outer periphery of said conductive member.

9. The connector of claim 1 wherein said conductive member is providedwith a longitudinal trough, said body of solder being disposed in saidtrough.

10. The connector of claim 3 wherein said conductive member is providedwith a recess in one surface thereof, said body of solder beingpositioned in said recess.

11. The connector of claim 3 wherein said body of solder is disposedaround the outer periphery of said conductive member.

12. The connector of claim 3 wherein said conductive member is providedwith a longitudinal trough, said body of solder being disposed in saidtrough.

13. The connector of claim 10 wherein said remainder of said tubularmember engages said conductor member except on said one surface.

14. The connector of claim 11 wherein the entire remainder of saidtubular member is spaced from said conductive member.

15. The connector of claim 12 wherein said remainder of said tubularmember engages said conductive member except in the region of saidtrough.

16. An electrical connecter comprising an elongated electricallyconductive member having side surfaces and top and bottom surfaces, arecess formed in said top surface adjacent the forward end of saidconductive member, a first indentation formed in each of said sidesurfaces approximately at the location of said recess, and a secondindentation formed in each of said side surfaces 1 said body of solder.

7 between said first indentation and said forward end; a body of solderpositioned in said recess; and a dimensionally heat unstable tubularmember position over said forward end of said conductive member and saidbody of solder, said tubular members being in intimate engagement withthe bottom surface of said conductive member, the side surfaces thereofto the rear of said second indentations, and the top surface thereof tothe rear of 17. The connector of claim 16 wherein said tubular membercomprises a cross-linked polymer.

18. The connector of claim 17 wherein said tubular 7 member comprises anirradiated polymer.

19 An electrical connector comprising an elongated electricallyconductive member having side surfaces and top and bottom surfaces, arecess formed in said top surface adjacent the forward end of saidconductive member, a first indentation formed in each of said sidesurfaces approximately coextensive with said recess, a secondindentation formed in each of said side surfaces between said firstindentation and said forward end, and

end of said tang, and the top surface between said body of solder andthe end of said tang. I

20. An electrical connector comprising an elongated electricallyconductive member having side surfaces and top and bottom surfaces, arecess formed in said top surface adjacent the forward end of saidconductive member and extending along an appreciable length thereof, afirst indentation formed in each of said side surfaces approximately atthe location of said recess, a second indentation formed in each of saidside surfaces between said first indentation and said forward end; abody of solder positioned in said recess; and a dimensionally heatunstable tubular member positioned over said forward end of saidconductive member and said body of solder, the longitudinal axis of saidtubular member being substantially parallel to the longitudinal axis ofsaid conductive member, said tubular member being heat recovered intointimate engagement with the bottom surface of said conductive member,the side surfaces thereof to the rear of said second indentations, andthe top surface thereof to the rear of said body of solder whereby aspace for receiving an electrical conductor is formed between saidtubular member and said body of solder, said space being narrower in thevicinity of said body of solder than at the forward end of saidconductive member.

21. An electrical connector comprising an elongated electricallyconductive member having side surfaces and top and bottom surfaces, arecess formed in said top surface adjacent the forward end of saidconductive memtrical conductor inserted therein will be berand extendingalong an appreciable length thereof, a first indentation formed in eachof said side surfaces approximately at the location of said recess, a'second indentation formed in each of said side surfaces between saidfirst indentation and said forward end; a body of solder positioned insaid recess; and a dimensionally heat unstable tubular member positionedover said forward end of said conductive member and said body of solder,the longitudinal axis of said tubular member being substantiallyparallel to the longitudinal axis of said conductive member, saidtubular member being heat recovered into intimate engagement with thebottom surface of said conductive member, the side surfaces thereof tothe rear of said second indentations, and the top surface thereof to therear of and on either side of said body of solder, and being heatrecovered toward the remainder of said top surface, said heat recoverybeing more pronounced in the vicinity of said body of solder than in thevicinity of the forward end of said conductive member whereby a spacefor receiving an electrical conductor is formed between said tubularmember and the top surface of said conductive member, said space beingmore restricted at said body of solder than at said forward end of saidconductive member whereby an elecguided to said body of solder.

22. An electrical connection comprising an elongated electricallyconductive member having side surfaces and top and bottom surfaces, arecess formed in said top surface adjacent the forward end of saidconductive member, a first indentation formed in each of said sidesurfaces approximately coextensive with said recess, a secondindentation formed in each of said side surfaces between said firstindentation and said forward end, and a spring-like tang attached to oneof said side surfaces and being normally flexed so that its end extendsabove said top surface; a body of solder positioned in said recess; anda dimensionally heat unstable tubular member positioned over saidforward end of said conductive member and said body of solder, saidtubular member being heat recovered into intimate engagement with thebottom surface of said conductive member, the side surfaces thereof, andthe top surface thereof to the rear of said body of solder; and anelectrical conductor having a conductive portion and an insulatedportion positioned in the space between said tubular member and saidconductive member with the conductive portion thereof immersed in saidbody of solder and the insulating portion thereof being intimatelyengaged by said tubular member.

References Cited UNITED STATES PATENTS 2,588,172 3/1952 Snavely et al.339-275 X 3,126,619 3/1964 Brent 174'84 X 3,243,211 3/1966 Wetmore174--84 LEWIS H. MYERS, Primary Examiner.

D. L. CLAY, Examiner.

1. AN ELECTRICAL CONNECTOR COMPRISING AN ELONGATED ELECTRICALLYCONDUCTIVE MEMBER; A BODY OF SOLDER POSITIONED ON SAID CONDUCTIVE MEMBERADJACENT ONE END THEREOF AND EXTENDING ALONG AN APPRECIABLE LENGTH OFSAID CONDUCTIVE MEMBER; AND A DIMENSIONALLY HEAT UNSTABLE TUBULAR MEMBERPOSITIONED OVER SAID ONE END OF SAID CONDUCTIVE MEMBER AND THE BODY OFSOLDER POSITIONED THEREON, THE LONGITUDINAL AXIS OF SAID TUBULAR MEMBERBEING SUBSTANTIALLY PARALLEL TO THE LONGITUDINAL AXIS OF SAID CONDUCTIVEMEMBER, A PORTION OF SAID TUBULAR MEMBER BEING IN INTIMATE ENGAGEMENTWITH SAID CONDUCTIVE MEMBER IN A REGION OF SAID CONDUCTIVE MEMBERBETWEEN SAID BODY OF SOLDER AND THE OTHER END THEREOF.